nature writing from a country warden

Menu

River Stour Internal Drainage Board

November began with a meeting between staff from the Stour Internal Drainage Board and their contractors Rhino Plant to review the cutting of Shalmsford Street Dyke.

The dyke once supported white clawed crayfish and was a nursery ground for trout but has become degraded with silt covering gravels and an excess growth of watercress across the channel.

excess watercress in stream

These problems are exacerbated by high nitrate levels and poaching of channel banks by livestock. Sheep stand in the channel to graze the watercress causing further poaching and nutrient enrichment.

Fencing would be one solution but landowners often don’t want the expense. Fencing can also cause problems for rivers if the fence line is too close to the channel edge and prevents bankside management. When this happens river banks can begin to scrub up creating dark channels which are impossible to manage.

During the meeting we looked at ways the cutting of the channel could help alleviate the situation. Narrow channels are often faster flowing with better oxygen levels and less silt drop out but this needs to be balanced against flood risk.

We decided that parts of Shalmsford Street will be cut manually which creates less disturbance to the channel bed and can give a more sinuous cut working with the natural processes of the river while other parts will be machine cut in order to create more open conditions to allow for winter water levels.

A further meeting took place with the IDB and EA in the middle of the month to talk about improvements to Buxford Dyke, near Ashford. Again poaching by livestock is causing issues here, pushing banks and silt into the river where it can cover gravels. Other sections of this channel are prone to drying out and there is potential to create off line ponds which could provide refuge for macro invertebrates during drought periods. Further discussions are needed with landowners before work can take place.

November also saw the annual IDB AGM where I gave a presentation to the board on the work we have completed in the last year and some of the challenges we face including managing invasive species on Chislet marshes and deciding which IDB channels to reduce maintenance on as we take on management of main river channels as part of the Environment Agency Rationalisation programme.

The Rationalisation Project looks at changing the status of some of our main rivers downgrading some of the smaller channels to Ordinary Watercourses. This would allow the Environment Agency to reduce the cost of its maintenance programme.

Lampen Stream is a channel which could be transferred to IDB management

It is proposed that the downgraded rivers are managed by the Internal Drainage Boards, whose costs are met by landowners who pay drainage rates for the channels to be managed. Several areas have been chosen to trial the project and the River Stour board is potentially one of the pilot areas, chosen partially because of its good environmental track record.

As the River Stour Board takes on the maintenance of more kilometres of river then they need to reduce maintenance on channels they currently manage. One of my main areas of work at the moment is deciding which channels would most benefit from reduced maintenance.

This project offers great potential to improve habitat for species such as Shining Ramshorn snails who like rivers with more in-channel weed and I have been liaising with Kent Wildlife Trust to choose which ditches in areas like the Ash Levels would benefit the most. Other species prefer more open water habitat and here I have been talking to the County Plant Recorder to make sure that channels with species such as hair like pondweed continue to be managed on an annual basis.

tubular water dropwort may benefit from reduced maintenance

This will create one of the biggest changes in the drainage district for many years but one which provides exciting opportunities for wildlife.

October has been a busy month, working with farmers across Kent to improve marshland and rivers for wildlife.

The North Kent Breeding Wader project is gaining pace helped by a grant scheme administered by Kent Wildlife Trust. This funding scheme gives grants to landowners to undertake work on their land for the benefit of wetland wildlife. Almost all the farmers I worked with applied for the grant and, while the land is still dry, they have been busy creating scrapes, restoring rills, fixing pumps and improving water control.

Mid month I joined farmer Mr Wood and contractors Taylor Bros near Conyer to scrape back rush from an overgrown rill in order to create bare earth ideal for lapwings to feed on.

Surveys carried out by KWT had shown there were no water vole present and so we could use the opportunity to create a shallow sloping edge. Good visibility is important for ground nesting birds so they can see and drive off predators. Crouching down at the water’s edge, I tried to look at the world from a lapwings point of view in order to get the correct bank profile.

This month also saw the completion of the first round of parrots feather removal from Chislet Marshes near Birchington on Sea. The River Stour Internal Drainage Board worked with Kentish Stour Countryside Partnership volunteers to remove every fragment of the plant from 500m stretches of the upstream reaches of three channels which the plant has colonised.

Volunteers from KSCP search for Parrot’s feather on Chislet Marshes

In future years we hope to work slowly downstream pulling out the plant from the margins as it is hopefully eradicated from the upper reaches. This approach has been chosen so that we can remove the invasive without damaging other marginal flora .

Officers from the EA and IDB discuss improvements for white clawed crayfish.

Lastly this month I met with white clawed crayfish experts from the Environment Agency to talk about management of channels which are proving strongholds for these endangered creatures. Working with the landowners and the IDB we hope to cut the weed from the channels in a way which will help maintain connectivity between isolated populations and add cobbles to the channel to give the crayfish places to shelter under.

September and the weed cutting season for the River Stour Internal Drainage Board is well under way.

The banks and weed are cut every summer as part of the general maintenance programme and one of my key jobs is advising on the best cut to maintain the wildlife interest of the channel and work with the contractors Rhino Plant to advise on particular areas of importance such as management for white clawed crayfish.

This month I worked with the Kentish Stour Countryside Partnership volunteers to tackle an invasive plant, Parrot’s feather, which has colonised ditches on Chislet marshes.

A small amount of this pond plant found its way into a roadside ditch and has spread quickly. Removing the plant needs to be sensitively managed so as not to cause disturbance or damage to other wildlife. Therefore spraying and vigorous weed cutting is not an option as both these methods would leave ditch edges bare of cover for other species.

Instead the River Stour IDB has approved a programme of mechanical weedcutting followed up by hand pulling of parrot’s feather from the margins. KSCP volunteers have already spent two days wading in the channel or paddling in boats as dragonflies buzz overhead.

An eagle eye is needed to spot the tiniest fragment of plant and a boom net has been installed to catch plants floating downstream. Despite their best attempts all involved know it will take many years of work to combat this plant.

Towards the middle of the month I attended an excellent course in wet grassland management run by the RSPB at their Otmoor reserve. Over two days I learnt about the precise needs of different waders and came away with lots of ideas to take out to farmers this autumn.

Simple changes such as rotovating foot drains can make a big difference and hopefully, by implementing these measures, we can continue to improve the fortunes of birds such as lapwings on the north Kent marshes.
Now all we need is a wet winter to top up the ditches and flood the grassland fields ready for the following spring.

August was a busy month with river surveys for the River Stour Internal Drainage Board.

The Board manages a huge variety of channels from small natural wooded streams, to wide drainage channels across former marshland to urban rivers.

Some of the channels offer ample opportunity for enhancements such as at Buxford Dyke in Ashford, a channel which traditionally supported white clawed crayfish. Fencing cattle from streams, removing weirs and installing cobbles in the channel could all help manage silt and provide hiding spots for crayfish.

cattle can cause issues with silt downstream

Sometimes the easy part is knowing what could be done to benefit the river. The harder task is persuading authorities and landowners that the work will be beneficial and not increase flood risk.

Traditional management practices sometimes involved drastic measure such as setting fire to channel banks and widening channels by dredging. These practices often were disastrous for wildlife and stored up issues for the future as widening narrow streams allows more silt to drop out in the centre of the channel creating a fertile ground for weed growth which blocks channels and may lead to flooding. More work needs to be done to show river managers and landowners that natural management techniques, such as allowing woody debris to remain in the channel can be beneficial.
Urban channels have different issues and Pumping Station Dyke, also in Ashford, suffers from fly tipping, invasive species and terrible bankside management by local businesses. Surveying a channel such as this it is easy to despair at the disregard many people show to their local areas and the low status of rivers in towns. With a channel such as this joined up thinking is needed for local bodies to work together to tackle issues such as fly tipping and misconnected sewers.

The month ended with a visit to Bourne Dyke, a beautiful channel set amid wet woodland with some fantastic old pollarded trees. Here the landowner has shown an interest in making improvements for wildlife and it is easy to get enthusiastic at the opportunity this could provide for restoring the natural wetland areas of this valley.

good use by identifying the many species of rushes and sedges that grown along this botanically rich channel. The waterway supports rare plants such as Tubular Water Dropwort and Hairlike Pondweed. My work involves advising the Drainage Board on how to manage the channel to benefit these and other species and look at ways of improving its value for wildlife.

Unfortunately many of our waterways suffer from Nitrate and Phosphate pollution often caused by historically overloading the land with fertilisers. Agrochemicals are big business and firms have lobbied farmers for fifty years to buy them in order to achieve higher yields and cut down on ‘pest’ species. Often land is overburdened with chemicals and much ends up seeping through the soil and fertilising rivers and drainage ditches which then sprout lush growths of plants such as watercress which can impede flow and cause flooding.

Excessive weed growth caused by chemical enrichment.

Over 8 years of surveying for the board I have also seen a change in land use with formerly grazed fields becoming fallow or cut for silage and more maize being grown. These changes are not good news for wildlife. Ditches alongside grazing marsh are often botanically rich as the action of animals grazing the channel opens up niches for wildlife while maize crops are often bad news next to rivers as after harvesting, the field is left with bare earth which can be washed into rivers in winter storms creating siltation issues which can lead to flooding.

Despite years of environmental subsidy schemes for farmers it seems that more needs to be done to tailor advise to farmers and put a healthy and wildlife rich countryside at the centre of farming policy not just tinker at the edges of farms and ignore the real issues.

However, the Internal Drainage Board are working to improve watercourses and this month I returned to Port Rill with volunteers from the Kentish Stour Countryside Partnership to finish installing woody debris in the channel. Fallen dead branches were pinned into place by the volunteers and should help create shallow marginal shelves along the edges of the channel while creating faster flow in the centre, cleaning gravels and creating oxygen rich water. This month we saw fish in this channel for the first time, a real testament to the volunteer’s efforts.

A month of river work finished with a survey of Pig Brook, another IDB managed channel which holds one of the last populations of White Clawed Crayfish. This native species is suffering through the spread of Crayfish plague spread from imported signal crayfish as well as pollution and silt covered gravels.

Earlier in the month I had given a talk to the drainage board’s contractors Rhino Plant on the importance of biosecurity and the need to check clean and dry equipment and spray with a specialised Iodine based spray when working on crayfish channels.
Pig Brook is an attractive channel set in parkland but more could be done to improve the stream for crayfish and connect it with the surrounding floodplain. Next month I hope to work on plans to enhance the river and allow the crayfish to thrive.

May continued to be packed with breeding wader surveys on 13 farms across North Kent.
This year it seems that some of the farmers had really cracked it when it comes to water and grass management.
In what has been an exceptionally dry spring some farmers have managed to hold water onto their land and this, along with grazing meant that we saw birds breeding on sites where they hadn’t been in twenty years. Even sites which are located amid industry and powerlines can produce results if the management is right and the site of lapwings swooping amid a backdrop of supermarkets and car plants on Sheppey filled me with joy.

A tree with high potential as a bat roost

Josh and I also attended an excellent course on Bats and Aboriculture run by the Bats Conservation Trust in Richmond Park . Over two days we learnt about the law regarding tree work and bat roosts, how to identify bat signs and use an endoscope. Josh, a qualified aboriculturalist, and I hope to use this work Autumn to identify potential bat roosts and advise land owners on correct management.
In the middle of the month I spent a day out on Chislet Marshes with Rhino plant controlling parrot’s feather on behalf of the River Stour IDB. This invasive plant has colonised an extensive area of ditch on the marshes and will take many years to control. Due to the extensive water vole population management it is important to not remove too much marginal vegetation and, following extensive survey work and advice, it was felt that the best approach was a strong weed cut in the autumn with booms placed in the channel to prevent fragments floating downstream followed up with hand weed pulling on the margins throughout the spring and autumn.
A bird survey of the channel identified areas where it was safe for the guys to work and John Waller and team worked hard to remove each small fragment of the plant. Later this year I will be working with the Kentish Stour Countryside Partnership volunteers to continue this work.Lastly the KSCP volunteers did some excellent work at Port Rill where the IDB have undertaken enhancement work installing woody debris in the channel. This work was completed in the winter and the improvements have been excellent. A previously sluggish and silty channel has begun to assume a more natural profile with meanders and riffles forming and the wide berms are becoming colonised by a diverse range of plants. The volunteer team worked to install faggots and smaller woody debris to the existing berms to create more micro habitats of benefit to fish and aquatic invertebrates.

Volunteers from the Kentish Stour Countryside Partnership glow with pride at their morning’s work.

It’s been an incredibly busy month as we prepare for the start of the survey season. The month began with a survey of channels on Chislet marshes for the River Stour Internal Drainage Board. We spent a day plotting the extent of the invasive species parrot’s feather which has unfortunately found its way into the ditch system. If left untreated the plant will shade out our native flora, clog structures and block sunlight from the water which will de-oxygenate it and lead to a loss in aquatic invertebrates.

invasive parrot’s feather growing on Chislet Marshes

“This is a particularly difficult situation,” said Carol. “The plant has spread rapidly and colonised a large area of the marshes. It is entwined with marginal vegetation along ditches which are a water vole stronghold. The challenge is to find a way of removing the plant while acting sensitively towards other species.”

To deal with this challenge Carol has sought advice from the Environment Agency and Andrea Griffiths, Senior Partnership Officer at Medway Valley Countryside Partnership, who has extensive experience at dealing with invasive species.

“Partnership working is really useful for issues such as this as we can all draw on each other’s experience to achieve a good result.”

The plant was quite possibly unintentionally introduced to the waterways by a member of the public, who may have been tipping excess frog spawn from a garden pond. Unfortunately this has resulted in years of expensive work for others.

On a brighter note we are delighted with the progress of many of the farms we visited this month as part of our advisory work on breeding waders.

Farmers have really taken on board the advice given in the autumn and have performed miracles in making grassland wet in what has been a very dry year. Topping and improved grazing regimes has resulted in much better sward conditions and many farmers have signed up to the funding available from the North Kent Capital Grant Scheme, administered by Kent Wildlife Trust.

Now we are all keeping our fingers crossed for good weather conditions this spring so the hard work can produce tangible results in the form of more wader chicks successfully fledged in North Kent.

volunteers removing litter from the channel.

Lastly we were delighted to work once again with volunteers from the Kentish Stour Countryside Partnership in order to improve a small, urban stream in Canterbury, managed by the River Stour Internal Drainage Board. This rather sad little channel was full of litter, carelessly thrown by passing motorists and had become dark and shady in some sections and overly managed by neighbouring business’s in others.

Over two days the volunteers cleared around forty bags of litter from the channel, cut back overhanging trees and planted 100 colourful wetland plants outside the Mercedes Garage on Sturry Road. Many thanks to Mercedes for providing drinks and sweets. Serco for removing the litter but mostly to the excellent volunteers who it is always a joy to work with.